Circuit interrupters are electrical components that can be used to break (or open) an electrical circuit, interrupting the current flow. A basic example of a circuit interrupter is a switch, which generally consists of two electrical contacts in one of two states; either closed, meaning that the contacts are touching and electricity can flow between them, or open, meaning that the contacts are separated, and no electricity can flow between them.
Another example of a circuit interrupter is a circuit breaker. A circuit breaker may be used, for example, in an electrical panel to limit the electrical current being sent through connected electrical wiring. A circuit breaker is designed to protect an electrical wiring and associated electrical components from damage caused by an overcurrent condition such as, a short circuit or a ground fault (collectively referred to as a fault condition). If a fault condition such occurs in the electrical circuit, the breaker will trip. This will cause a breaker that was in the “on” position to flip to the “off” position and interrupt the flow of electrical energy through the circuit breaker. When a circuit breaker is tripped, it may prevent a fire from starting on an overloaded circuit; it can also prevent damage to or the destruction of any devices that are drawing electricity from electrical circuit.
A standard circuit breaker has a terminal connected to a power supply, which may comprise electrical power provided by a power company. A standard circuit breaker also typically includes another terminal to which the electrical circuit is connected that the circuit breaker is intended to protect. Conventionally, these terminals are referred to as the “line” and “load” terminals respectively. The line is often referred to as the input into the circuit breaker; whereas the load is often referred to as the output. The output supplies electrical energy to the electrical components connected to the electrical circuit.
A circuit breaker may be used to protect an individual device, or a number of devices. For example, an individual protected device, such as a single air conditioner, may be directly connected to a circuit breaker. A circuit breaker may also be used to protect multiple devices by connecting to multiple components through wiring that terminates at electrical outlets. In this manner, the circuit breaker feeds electrical power to all the devices connected to the circuit via the outlets (e.g., a lamp, a television, a computer, etc.). In other configurations, circuit breakers may be for special use, for example, they may be provided in a rack in a server room where a certain number of servers are connected to a particular circuit breaker.
A circuit breaker can be used as a replacement for a fuse. Unlike a fuse however, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are generally considered safer to use than fuses. For example, in a situation where a fuse blows, interrupting power to a section of a building for example, it may not be apparent which fuse controls the interrupted circuit. In this case, all of the fuses in the electrical panel would need to be inspected to determine which fuse appears burned or spent. This fuse would then need to be removed from the fuse box, and a new fuse would need to be installed.
In this respect, circuit breakers can be much simpler to use than fuses. In a situation where a circuit breaker trips, interrupting power to a section of a building, for example, it may be easily apparent which circuit breaker controls the interrupted circuit by looking at the electrical panel and noting which breaker has tripped to the “off” position. Conventional circuit breakers include a switch on the face of the breaker where the switch is moved to the center of the electrical panel for “on”, toward the perimeter of the electrical panel for “off” and will reside in a center position for “fault.” This breaker can then be visually identified and reset. If the circuit breaker is in a fault state, the handle needs to be moved to the “off” state and then to the “on” state and power will be supplied to the connected electrical circuit.
In general, a typical circuit interrupter has two contacts located inside of a housing. The first contact is stationary, and may be connected to either the line or the load. The second contact is movable with respect to the first contact, such that when the circuit breaker is in the “off” or tripped position, a gap exists between the first and second contact.
U.S. Pat. No. 3,443,258 (the '258 patent”) entitled Circuit Breaker With Trip Indicator provides a circuit breaker with a window that has a flag painted in a red color, such that, when the circuit breaker transitions into a tripped or fault condition, the red flag will be shown in the window providing a visual indication that the circuit breaker has experienced an overcurrent condition and must be reset. In either the On or the Off position, the red flag is hidden. The flag is coupled to the trip lever via a linkage, which in some configurations comprises a spring. One limitation of the '258 patent is that there is no visual indication in the window to differentiate between the On position or the Off position. To do this, one would have to look at the position of the handle relative to the housing. In other words, the window only provides information relating to whether the circuit breaker is tripped or in a fault state.
One particular actuator configuration is a rocker actuator. A rocker actuator provides a discrete or very low profile on/off actuator. These actuators have many applications including light switches, general power switches, and actuators in circuit breakers. Circuit breakers using a rocker actuator are very suitable for use in power rack configurations in server rooms to feed rack mounted servers where space is at a premium in the environmentally controlled space.
In operation, activation or deactivation of the rocker actuator (On or Off), causes a mechanical movement inside of the housing. When the user activates the actuator, the portion of the actuator (the rocker) that is outside of the housing is moved. The actuator is connected to a pin, which causes a subsequent movement inside of the housing, either completing or disconnecting a circuit (opening or closing the switch).
However, in a rocker actuator design used in connection with a circuit breaker, the physical movement of the actuator is more difficult to visually detect than a standard handle on a circuit breaker. For example, a standard handle extends well outside the housing and is displaced laterally (e.g. typically from side to side) such that it is fairly easy to visually determine the state of the circuit breaker by simply looking at the position of the handle. In a rocker actuator configuration, there is effectively no lateral movement, but rather one side of the switch is displaced inward relative to the housing of the circuit breaker and the other side is displaced upward relative to the housing. However, when looking straight on at the top surface of the circuit breaker housing, it can be difficult to determine the state of the circuit breaker without physically feeling position of the rocker switch or looking at it from an oblique angle, which may not even be possible in server room installations due to space constraints. Additionally, if the rocker actuator does not include a mechanical latching feature such that, when not being physically activated the rocker actuator reverts to a center position, there is no way to determine the status of the circuit breaker visually. It could be that there is no handle position that can provide a status indication.
It is therefore desired to provide an alternative system that is usable with a circuit interrupter that overcomes the aforementioned limitations.